At times outlook is loosing connection to Exchange Server and after few seconds it re-establishes the connection. the client is outlook 2007 and we have exchagne server 2007. The client is located in different site from the server. I have checked with users in the same site as the exchange and they are not facing this issue,therefore, it is not an exchange server which is causing this. So, I checked with network team, and even they are sure that nothing from network is blocking or causing any issues. So, I am stuck now, I saw the following logs in client machine and would like to know if some one has faced this kind of issue and the suggested way to troubleshoot this;Event Type:InformationEvent Source:OutlookEvent Category:NoneEvent ID:19Date:11/16/2009Time:4:38:25 PMUser:N/AComputer:RO-TESTDescription:Rpc call (EcDoDisconnect) on transport (ncacn_ip_tcp) to server (server name) failed with error code (6) after waiting (1594) ms; eeInfo (none). For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp. Event Type:InformationEvent Source:OutlookEvent Category:NoneEvent ID:19Date:11/16/2009Time:4:38:24 PMUser:N/AComputer:RO-TESTDescription:Rpc call (EcDoDisconnect) on transport (ncacn_ip_tcp) to server (server name) failed with error code (6) after waiting (907) ms; eeInfo (none). For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp. Enabled Outlook Loggingt :================================Found a transport, Error code = 0x00000000 2009.11.16 16:28:04 MAPI Status: (IN -- ---/OUT -- ---)2009.11.16 16:28:04 MAPI XP Call: TransportNotify(BEGIN_IN|BEGIN_OUT), hr = 0x000000002009.11.16 16:28:04 HELPER::Initialize done, Error code = 0x000000002009.11.16 16:28:04 HELPER::GetCapabilities called, Error code = 0x00000000

Error event is just for the operation timeout Whats the connection between two sites? Does the issue happen permanently to all clients on that different site? After reconnect to the exchange server, please check the Connection Statusof the problematic client. Does the connection switch from TCP to HTTPS? Please enable the logging again, reproduce the issue, and then send me the ETL log for analyzingJames Luo TechNet Subscriber Support (http://technet.microsoft.com/en-us/subscriptions/ms788697.aspx) If you have any feedback on our support, please contact tngfb@microsoft.com

I have seen some packet drops when I do a continous ping from the client machines, though its a 1 or 2 packets out of 300, but still I believe this would be the cause of the issue.I am still working with the netowrk guys.. Will update you with the results.

Rakesh,Looks like netowk issue. Can you try running Netmon from the client and server at the same time and see what kind of packet drop you are having. If you are on rpc over https , then also check the internet , if you can browse at the time of outlook timing out.Raj

Any update?James Luo TechNet Subscriber Support (http://technet.microsoft.com/en-us/subscriptions/ms788697.aspx) If you have any feedback on our support, please contact tngfb@microsoft.com

I have send you the logs.Thanks,Rakesh

According to the log files, theres a lot of trace for data retransmission. So, the network must have certain issue. Otherwise, the packages dont need to be retransmitted. I think you shall let network team take a look on it And please give me more information about the network trace you send, like, which IP is for DC, exchange, the accurate timeslot that the connection is down and back, which side do you take the trace, and the likeJames Luo TechNet Subscriber Support (http://technet.microsoft.com/en-us/subscriptions/ms788697.aspx) If you have any feedback on our support, please contact tngfb@microsoft.com

Thanks a lot James. I have sent an email to you with details.Just wanted to know why is the EcDoDisconnect request appears in the log and what's the (Protocol: Mapi Info: Unknown ? Request/Protocol: Mapi Info: Unknown ? Response) ?signifies?Whenever the outlook disconnect happened it coincided with the above info in the log.

By the way, the ETL seem corrupted, theres no data in them. Based on the network trace: ============= 12626 214.778469 {MSRPC:681, TCP:680, IPv4:83}Client Server MSRPC MSRPC:c/o Request: Exchange Server STORE EMSMDB Interface {A4F1DB00-CA47-1067-B31F-00DD010662DA} Call=0x1 Opnum=0x1 Context=0x0 Hint=0x50 12630 214.837520 {MSRPC:681, TCP:680, IPv4:83}ServerClient MSRPC MSRPC:c/o Fault: Call=0x1 Context=0x0 Status=0x1C00001A Cancels=0x0 ============= In frame 12626, opnum 0x1 is being tried with an EcDoDisconnect, which is an attempt to disconnect from the information store. The resulting RPC fault in frame 12630, displays a status of 0x1C00001A, which is NCA_STATUS_CONTEXT_MISMATCH, the first indication of a problem Please check the relevant log files on the security appliances between the remote client and the server. And, at the time of the failures, any device that is capable to drop or block RPC packets could cause the issue In similar cases, CISCO router upgrade could just broke communication between sites while others worked fine. Also, certain filtering devices or an issue crossing a router/switch either between the server and the client or the server and the DC can cause it Resources: RPC cancel request dialogue box due to session timeout triggered by the Network devices Network Problems Are Preventing Connection to the Microsoft Exchange Server Computer James Luo TechNet Subscriber Support (http://technet.microsoft.com/en-us/subscriptions/ms788697.aspx) If you have any feedback on our support, please contact tngfb@microsoft.com

Thanks James. Surely, I will have my Network team to look at it. thanks again for all your help. I will update the thread in case we are able to find some thing ..

Sure. :)James Luo TechNet Subscriber Support (http://technet.microsoft.com/en-us/subscriptions/ms788697.aspx) If you have any feedback on our support, please contact tngfb@microsoft.com

Thanks Luo..the ISP has changed some of the network devices which were causing packet loss and for last 3 days we have not seen outlook getting disconnected. Thanks for all your help.

Cool!!James Luo TechNet Subscriber Support (http://technet.microsoft.com/en-us/subscriptions/ms788697.aspx) If you have any feedback on our support, please contact tngfb@microsoft.com

Was your problem with MAPI protocol only or any protocol? My problem is very simular to yours, and I still can't find an answer... http://social.technet.microsoft.com/Forums/en-US/exchangesvrclients/thread/109099d5-43aa-4014-b5fa-00b7fac9425f

The problem was only for Mapi. You may need to confirm if the problem you are facing is for a paticular client machine or for all in a particular location ?

I would check the connectivity between the client and the server.

In my case router’s MTU didn't match, so there was an issue with packet fragmentation. Since the issue was on the lower network level (transport), application errors were misleading. Srver side router had MTU set to 1500, client side was at 1492 Communications were breaking with data coming from the server to the client, but from the client to the server everything looked fine.